7-Methylxanthine is a methyl derivative of xanthine, found occasionally in human urine. 7-Methylxanthine is one of the purine components in urinary calculi. 7-methylxanthine (7-MX) is a metabolite of caffeine and theobromine, and has been shown to have low toxicity and no carcinogenic effects. 7-MX is known as a non-selective adenosine antagonist and has been shown to work against myopia. 7-MX has little effect on the proliferation or apoptosis of human RPE cells; however, 7-MX disturbs the proportion of cells in the G1 stage and inhibits the expression of ADORA1, ADORA2A, and ADORA2B in short-term treatment. 7-MX has been confirmed to reduce the severity of myopia and eye elongation induced by forming deprivation in guinea pigs and to counteract the thinning of the posterior sclera and of collagen fibrils induced by form deprivation. A clinical trial showed that 7-MX reduced eye elongation and myopia progression in childhood myopia.